This is a double-blind placebo-controlled study to evaluate the effect of Naltrexone (NTX) and counseling on highly active antiretroviral treatment (HAART) medication adherence in a cohort of HIV-infected patients who report heavy drinking, or meet criteria for alcohol abuse and/or dependence, and inadequate (< 95%) HAART adherence. All patients will receive a behavioral intervention, termed Medical Management/Medication Coaching or MM/MC. MM/MC incorporates the behavioral platform Medical Management (MM) from the National Institute on Alcohol Abuse and Alcoholism (NIAAA)-funded COMBINE Study to reduce heavy alcohol use with Medication Coaching (MC), a manualized treatment designed to improve HAART medication adherence in HIV-infected patients with substance use disorders.